Fluorine incorporation in organic compounds is known to have a profound influence on the physical and chemical properties such as biological activity and electronegativity. A trifluoromethyl group has been employed as an effective means for introducing fluorine into such compounds. An alternative to trifluoromethyl incorporation has been the addition of sulfur pentafluoride. The high electronegativity value of the SF5 group, 3.62 on the Pauling scale, and greater electron withdrawing ability suggest that it affords an attractive alternative to the trifluoromethyl group (“CF3”) found in many commercial products such as dye-stuffs, anesthetics, fluoropolymers, electronic components, and chemotherapeutic agents.
Pentafluorosulfanyl derivatives of aromatic compounds have been produced but the study of these compounds has been limited because of the lack of good synthetic routes. SF5 addition to fused aromatic compounds is unknown.
Representative articles and patents illustrating addition of a sulfur pentafluoride group to organic compounds are as follows:
U.S. Pat. No. 6,479,645 discloses the silyl sulfurpentafluoride and substituted ethyne compounds useful as a precursor for a variety of organic compounds. Substituted silyl acetylenic compounds are reacted with an SF5 halide under condition to form an vinyl pentafluorosulfuanyl intermediate followed by addition of base. SF5Br addition to trimethylsilylacetylene resulted in the product, pentafluorosulfuranyl-2-trimethyl silylethyne.
US 2003/0216476 A1 discloses the preparation of pentafluorosulfanylbenzoylguanidines. These compounds were found to be suitable as antiarrythmic agents and for treatment of angina pectoris.
JP 2004/059452A, discloses the preparation of N-ribo-benzimidazole bearing an SF5 group. This compound was found to be an effective anti-viral and anti-cancer agent.
Kirsch, et. al in Agnew. Chem. Int. Ed. 1999, 38, 13, 1989 reported in the article, Liquid Crystals Based Upon Hypervalent Sulfur Fluorides: Pentafluorosulfuranyl as Polar Terminal Group, disclose the application of aryl sulfurpentafluorides as liquid crystals and demonstrated an improved electro-optical property of the —SF5 group over the —CF3 group. Pentafluorosulfuranylbenzene derivatives were produced by direct fluorination of deactivated aromatic disulfides.
Sheppard and co-workers, J. Am. Chem. Soc. 1962, 84, 3064 disclose in an article Arylsulfur Pentafluorides, the reaction of aryl disulfides with silver difluoride to obtain phenyl sulfurpentafluoride and nitrophenyl sulfurpentafluoride in ˜30% yield.
Bowden et al, Tetrahedron, 2000, 56, 3399, in an article A New Method for the Synthesis of Aromatic Sulfurpentafluorides and Studies of the Stability of the Sulfurpentafluoride Group in common Synthetic Transformations, disclose the reaction of aryl disulfides with F2 in the presence of CH3CN to produce nitrophenylsulfurpentafluorides. The nitrophenylsulfurpentafluorides then were converted to aminophenyl sulfurpentafluorides, biphenylsulfurpentafluoride, acetamidophenyl sulfurpentafluoride, and the like.
Hoover et al, J. Am. Chem. Soc. 1964, 3567 in an article entitled, Synthesis And Chemistry Of Ethynylsulfur Pentafluoride disclosed a procedure to phenyl sulfurpentafluoride and dimethylphenyl sulfurpentafluoride involving a Diels-Alder cycloaddition reaction of butadiene and 2,3-dimethylbutadiene respectively with ethynyl sulfurpentafluoride.
WO 011422A1 discloses the preparation of pentafluorosulfanylbenzene via the reaction of SF5Cl with 4,5-dichloro-1-cyclohexene and pentasulfanylalkenes by reacting SF5Cl with an alkene.